[영문]Purpose: This study explores the effects of participation in a program designed to enrich friendship and reduce loneliness among women in later life. Several hypotheses based on the need to belong, socioemotional selectivity theory, and the social compensation model were tested. Design and Methods: Study 1 involved two measurement points, one at the end of the program and the other 1-year later. Study 2 used a pretest?post-test control group design with a follow-up measurement. A combination of semistructured interviews and structured questionnaires was used to collect data. A comparison group was also drawn from a nationwide representative sample. Results:Participants were characterized by deprivation on the need to belong; that is, loss of a partner, higher levels of loneliness and negative affect, and lower positive affect compared with a nationwide representative sample of same-aged women. Participants were more likely than women in a control group to report the development of new friendships and an improvement in friendship. The combination of new and improved friendships contributed to a significant reduction in loneliness within a year. There was no evidence of satiation of the need to belong among those who did not expand or improve friendships. Loss of a partner had no influence on friendship development; however, age did. Older participants were less likely to improve friendships. Implications: The action-oriented approach that focused on friendship development in this intervention might be applied to other goals considered important in later life (optimal health, autonomy, harmonious family relations).